250701_42 ERW_Stormwater Report

NOAA 24-hr D 25-Year Rainfall=6.44" 250624_42 ERW Waymaker Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 14 Summary for Subcatchment PR 2-P: [49] Hint: Tc<2dt may require smaller dt Runoff = 0.76 cfs @ 12.11 hrs, Volume= Routed to Reach DP2-PR : 0.053 af, Depth= 3.76" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 25-Year Rainfall=6.44" Area (sf) 6,447 958 7,405 7,405 CN 74 89 76 Description >75% Grass cover, Good, HSG C Gravel roads, HSG C Weighted Average 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.6 84 0.0833 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 3.44" Subcatchment PR 2-P: Hydrograph Runoff 0.8 0.76 cfs 0.75 0.7 0.65 0.6 Flow (cfs) 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 NOAA 24-hr D 25-Year Rainfall=6.44" Runoff Area=7,405 sf Runoff Volume=0.053 af Runoff Depth=3.76" Flow Length=84' Slope=0.0833 '/' Tc=4.6 min CN=76 0.1 0.05 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 Time (hours)